Thermal conduction of heat from a motor during motor operation is required to maintain a motor operating temperature which is not detrimental to the motor or motor components. Heat transfer from a motor may be restricted by one or more clearance gaps or air spaces between components of the motor, such as between a stator and a motor housing, which reduce heat transfer from the motor due to the poor thermal conductivity, e.g., the insulating properties, of the air present in the gap or space.
Elevated operating temperatures may affect motor efficiency by increasing the energy input required to generate torque output, or may affect motor performance or durability by thermally stressing the motor and increasing the potential for thermal fatigue of motor components such as windings. Motor control systems may be configured to monitor motor temperature and to restrict motor output to a maximum torque limit to prevent overheating of the motor in situations where heat transfer is insufficient to maintain the operating temperature of the motor below a temperature limit.